Even as an 8, you've just paid more in grading fees than the card is worth.
The last two PSA 8 sales have been $15.50 and $16.99. Here's one from a couple of days ago:
Temple PSA 8
I (somewhat) understand when people are attempting to play these games when the price jump is hundreds or thousands of dollars, but I can't see why it'd be worth it for a card like this, gum stain or no gum stain....